This study is designed to determine the maximum tolerated and recommended Phase II dose(s) of the topoisomerase inhibitor J-107088 when given as a two-hour infusion once every 21 days. It will describe the toxicities of J-107088 both qualitatively and quantitatively and investigate the clinical pharmacokinetics and pharmacodyamics of J-107088. As secondary objectives, the study will describe the anti-tumor activity of J-107088 and develop a profile of toxicity of J-107088. This study involves one 36-hour in-patient monitoring period. Seventeen timed blood samples are drawn during this period. After the first admission, patients return to the GCRC outpatient clinic. Single blood samples are drawn 48 and 72 hours after the start of their first J-107088 infusion. Patients are asked to give a urine sample before the infusion of J-107088. Then urine is collected for 24 hours during the admission to the GCRC, and over the next 2 days.